6. Passive Congestion of the Stomach.—This embraces an important group of causes of gastric hemorrhage. This hemorrhage is the result of venous congestion caused by some obstruction to the portal circulation. The obstruction may be—
a. In the portal vein itself or its branches within the liver, as in pylethrombosis, cirrhosis of the liver, tumors, such as cancer or echinococcus cysts, compressing the portal vein, occlusion of capillaries in the liver by pigment-deposits in melanæmia, and dilatation of the bile-ducts in the liver from obstruction to the flow of bile. Next to ulcer and to cancer of the stomach, cirrhosis of the liver is the most frequent and important cause of gastrorrhagia.
b. In the pulmonary blood-vessels, as in pulmonary emphysema, chronic pleurisy, and fibroid induration of the lungs.
c. In the heart in consequence of uncompensated valvular and other diseases of the heart.
For evident reasons, obstruction of the pulmonary or of the cardiac circulation is much less likely to cause gastric hemorrhage than is obstruction in the portal vein or the liver.
Possibly, gastric hemorrhage which is caused by violent acts of vomiting may be caused by venous congestion of the mucous membrane of the stomach. In support of this view, Rindfleisch advances the idea that the veins in the muscular layers of the stomach, in consequence of the thinness of their coats, are much more likely than the arteries to suffer from the compression of the muscle during its contraction.
The occasional occurrence of gastric hemorrhage during pregnancy has also been attributed to passive congestion of the stomach.
7. Acute Infectious Diseases—namely, yellow fever, acute yellow atrophy of the liver, relapsing fever; less frequently cholera, typhoid fever, typhus fever, diphtheria, erysipelas, and the exanthematous fevers, small-pox, measles, and scarlet fever.
The cause of gastric hemorrhage in these diseases is not understood. The usual explanation attributes the hemorrhage to dissolution of the blood-corpuscles and secondary alteration of the walls of the blood-vessels. Plugging of the vessels with micro-organisms has been found in only a few instances. The gastrorrhagia of acute yellow atrophy of the liver has been attributed to dissolution of the blood, not only by some infectious agent, but also by constituents of the bile, and also to obstruction of the portal circulation by destruction and occlusion of capillaries in the liver.
8. Other Constitutional Affections.—a. Hemorrhagic diatheses—namely, scorbutus, purpura, and hæmatophilia. Strictly speaking, a hemorrhagic diathesis exists in other affections of this class.